We're happy to get more Dominion cards. But for people who play with all cards randomly, do you see a problem in having so many cards? Just because with only one or two sets, you are likely to get interesting kingdoms; with all sets, it is more likely to draw no-combo kingdoms, like 10 Villages.
For that reason, I created "card pools" that contain specific cards from each set which may be interesting to play with combined (like, "buying decisions", "cantrips", "combo with Copper", or just "power cards").
Do you recommend any restrictions on kingdom generating?
At some point transporting everything is too hard; I recommend not doing that. You can play with everything at home, or just bring a subset with you to a game night. You can have the subset be random if you do the thing where you have little packets of cards, a plastic thing holding the 10 copies of a card, and you just shuffle those around in a big box and grab some for the evening. Or you can just bring two or three boxes with you and play those cards. I have mostly only played with two expansions at once irl.
Using just a couple sets at once, you will see the synergies built into the sets more often. That's a benefit of playing just a couple sets. It's fun to mix it up too though.
When making a game such as this, it's an immediate question: can you get away with pure random. It's great if you can, but sometimes to make things work you have to compartmentalize to some degree. Obv. I felt I could get away with pure random with Dominion. Categories of cards that I want to appear at certain frequencies, appear at certain frequencies; when a particular category doesn't appear in some games, that's a feature not a bug. I have not noticed any issues when playing with a random mix of everything published plus the new set.
Things vary from set to set, and over time as I figured out what I was doing; but the idea has always been, that I can't assume you own any particular sets, and want the game to work for whatever mix of sets you own, and that means making each set provide a good amount of everything I care about.
As always I recommend that people do whatever they want. If you always want Moat in the game, I don't mind. I personally play pure random online (or, pure random except force N cards from the expansion being tested or something similar), and irl play with two expansions (usually 5 cards from each but not always). If you generate a random set of 10 and are displeased with it in some way, you can change it.